Certain mammalian cells in their normal state are characterized by rapid division and proliferation in the body, e.g., small intestinal epithelial cells, sperm cells, hair and skin cells, and hepatocyte or liver cells. Damage to, or depletion of, these cells can result due to certain diseases, infections, exposure to therapeutic agents and treatments, exposure to other chemical or biological agents, and injury or trauma.
For example, the use of chemotherapy and radiation therapy for the treatment of cancer and for the preparation of patients for bone marrow transplantation is toxic to the small intestinal (gut) epithelial cells. In fact, the small intestine is one of the organs most damaged by this therapy. Similarly damaged by such therapy are skin cells, hair cells and sperm cells. This cell damage, particularly to the gut cells, is the cause of significant mortality and morbidity in cancer patients undergoing therapy. Previously, such toxicity has been avoided by limiting the amount of chemotherapy or radiation administered to the patient. For example, gut cell toxicity has been diminished with radiation therapy by both decreasing the amount of radiation and giving the total dose subdivided into fractions (called `fractionation` therapy). However, the reduced amount of therapy also has an adverse effect on the spread and growth of the cancer against which it is directed.
Certain autoimmune diseases of the gut, such as Crohn's disease and ulcerative colitis, also have been known to damage the small intestinal cells lining the gut, causing major morbidity and mortality in patients so afflicted. Treatment of autoimmune diseases of the gut include chemotherapy and immune suppression, both of which have serious side effects, among them additional damage to the rapidly dividing gut cells.
Skin and hair cell populations may also be damaged by autoimmune diseases, burns, and alopecia. Sperm cell populations are damaged by oligospermia. Hepatocytes are also damaged by radiation, chemotherapy, and physical trauma.
Damage to gut cells, and to other cells which grow rapidly in a normal healthy mammal can also be the result of trauma or injury to the area, or shock. Exposure to certain industrial and household chemicals, among other agents, can also severely damage normal healthy populations of these cells.
There is a need in the art for methods for treating cell damage, particularly gut cell damage caused by disease or adverse effects of chemotherapeutic and radiation treatment, exposure to other damaging agents or trauma in mammals, particularly humans.